use pathToFileUrl to make esm import()s work with absolute windows paths

azure-pipelines.yml

@@ -69,8 +69,9 @@ stages:
           - script: npx playwright@1.35.1 install chromium
             condition: eq(variables['isDocsOnly'], 'No')
 
+          # Test critical app router and CNA tests to cover basic usage cases with windows
           - script: |
-              node run-tests.js -c 1 test/production/pages-dir/production/test/index.test.ts test/integration/css-client-nav/test/index.test.js test/integration/rewrites-has-condition/test/index.test.js
+              node run-tests.js -c 1 test/production/pages-dir/production/test/index.test.ts test/integration/css-client-nav/test/index.test.js test/integration/rewrites-has-condition/test/index.test.js test/integration/create-next-app/examples.test.ts test/integration/create-next-app/index.test.ts test/integration/create-next-app/package-manager/pnpm.test.ts
             condition: eq(variables['isDocsOnly'], 'No')
             displayName: 'Run tests'
 

packages/next/src/build/swc/index.ts

@@ -1220,7 +1220,7 @@ async function loadWasm(importPath = '') {
         // the import path must be exact when not in node_modules
         pkgPath = path.join(importPath, pkg, 'wasm.js')
       }
-      let bindings = await import(pkgPath)
+      let bindings = await import(pathToFileURL(pkgPath).toString())
       if (pkg === '@next/swc-wasm-web') {
         bindings = await bindings.default()
       }

packages/next/src/lib/find-config.test.ts

@@ -3,6 +3,7 @@ import { join } from 'node:path'
 import { tmpdir } from 'node:os'
 import { findConfig } from './find-config'
 
+// Jest does not support `import('file://something')` (file: imports) yet.
 describe('findConfig()', () => {
   const exampleConfig = {
     basePath: '/docs',

packages/next/src/lib/find-config.ts

@@ -1,6 +1,7 @@
 import findUp from 'next/dist/compiled/find-up'
 import { readFile } from 'fs/promises'
 import JSON5 from 'next/dist/compiled/json5'
+import { pathToFileURL } from 'url'
 
 type RecursivePartial<T> = {
   [P in keyof T]?: RecursivePartial<T[P]>
@@ -64,11 +65,27 @@ export async function findConfig<T>(
 
   const filePath = await findConfigPath(directory, key)
 
+  const esmImport = (path: string) => {
+    // Skip mapping to absolute url with pathToFileURL on windows if it's jest
+    // https://github.com/nodejs/node/issues/31710#issuecomment-587345749
+    if (process.platform === 'win32' && !process.env.JEST_WORKER_ID) {
+      // on windows import("C:\\path\\to\\file") is not valid, so we need to
+      // use file:// URLs
+      return import(pathToFileURL(path).toString())
+    } else {
+      return import(path)
+    }
+  }
+
   if (filePath) {
     if (filePath.endsWith('.js')) {
-      return isESM ? (await import(filePath)).default : require(filePath)
+      if (isESM) {
+        return (await esmImport(filePath)).default
+      } else {
+        return require(filePath)
+      }
     } else if (filePath.endsWith('.mjs')) {
-      return (await import(filePath)).default
+      return (await esmImport(filePath)).default
     } else if (filePath.endsWith('.cjs')) {
       return require(filePath)
     }